Refrigerating system



Oct. 24, 1933. s H, BRABS 1,932,007

REFRIGERATING SYSTEM Filed Ju1 y 5, 1932 2 Sheets-Sheet 1 I INVENTOR.

BY 4 MYW ATTORNEY.

Oct 24, 1933. E. s. H. BAARS 1,932,007

REFRIGERATING SYSTEM I Filed July 5, 1932 2 Sheets-Sheet 2 INVENTOR.

BY 7M ATTORNE Y.

Patented Oct. 24, 1933 TATES I UKTEE PATENT *orric REFRIGERATING SYSTEM Application July 5, 1932. Serial No. 620,813

llli Claims.

The present invention relates in general to improvements in the art of refrigeration, and relates more specifically to improvements in the construction and operation of controlling mechanisnis for refrigerating systems.

A general object of the invention is to provid improved control means for refrigerating systems, which means are simple and compact in construction and which are also automatic and 0 highly effective in operation.

it is frequently desirable in refrigerating plants, to supply the refrigerant from a single compressor and condenser, to two or more cooling units disposed either in the same or in different rooms or localities. Since the existing conditions in these several rooms or localities may be of widely varying nature, it is desirable to be able to effect independent control of the delivery of refrigerant and gases to and from each of the several cool ing coils or evaporators, and it is also desirable to have such control entirely automatic. If fans or other means are utilized for the purpose of circulating air within the refrigerated enclosures and for defrosting purposes, it is furthermore de sirable to effect independent and automatic control of the operation of these fans, and so far as known, no prior control systems have been capable of meeting all of these desirable conditions.

it is a more specific object of the present invention to provide an improved automatic control especially applicable to multiple-unit refrigeration systems, which will meet all of the above mentioned desirable conditions.

Another specific object of the invention is to provide mechanism for preventing over feeding of refrigerant to an evaporator, and consequent delivery of liquid refrigerant or slugs from the evaporator to the compressor.

A further specific object of the invention is to provide simple and effective means for insuring an abundance of liquid refrigerant supply to each of the series of evaporators supplied from a common source.

Still another specific object of the invention is to provide an improved air circulation control for refrigeration systems, wherein the air circulating means will be operated so as to effect maximum economy in power consumption.

A further specific object of the invention is to provide automatically operable control mechanism which is readily applicable to existing refrigeration systems for the purpose of improving the operation and economy thereof.

These and other objects and advantages of the present invention will be apparent from the following detailed description.

Some of the novel features of'automatic refrigeration system control, shown and described but not specifically claimed herein, form the subject of copending applications Serial Number 561,147 and Serial Number 561,148, both filed September 4, 1931 now Patent No. 1,916,197, patented July 4, 1933 and Patent No. 1,880,653, patented Oct. 1932, respectively.

A clear conception of embodiments of the several features constituting the present invention, and of the operation of refrigerating systems utilizing the improved automatic control, may be had by referring to the drawings accompanying and forming a part of this specification in which like reference characters designate the same or similar parts in the various views:

Fig. l is a diagram of a multi-unit refrigeration system embodying the improved automatic control; and

Fig. 2 is a typical wiring diagram of the elec trical end of a system involving the present in=- vention.

Referring specifically to Fig. 1, the multi-unit refrigerating system illustrated therein, comprises generally a single compressor 5 having a main suction line 6 and a discharge line 7 the latter of which communicates through a suitable receiver or header 8 with a condenser 9 which in turn communicates through another header 10 with a main feed line 11; and a plurality of independent refrigerating units associated with the main suction and feed lines 6, 7. While only two units have been illustrated, it will be understood that the main suction and feed lines 6, '7 may be utilized in conjunction with any desired number of these units located either closely adjacent to each other or at remote distances.

, Each of the several refrigerating units consists of a cooling coil or evaporator 12 usually disposed within an enclosure 13 and having lower and upper headers 14, 15 associated with the inlet and discharge ends thereof; an accumulator 16 having a well 16' the lowermost portion of which communicates with the lower header 14 through a pipe 17, and the upper gas chamber of which accumulator 16 is directly connected with the upper header 15 through apipe 18; and pipe connections and mechanism for automatically controlling the delivery of refrigerant to and from the accumulator l6. Disposed at one end of the accumulator '16, is a float controlled needle valve 19 operable by a float 20 whichrides upon the liquid refrigerant within the accumulating chamher, and which controls the flow of refrigerant from the pipe 21 to the pipe 22 the latter of which communicates directly with the well 16 of the refrigerant accumulator 16. The interior of the well 16 is provided with a partition 17' extend ing downwardly from a point Within the accumulator 16 above the top' of the well, to a point somewhat above the bottom of the well 16, and the pipes 17, 22 communicate with the interior of the well on opposite sides of this partition 17 as clearly shown in Fig. 1. This construction insures uniform flow of liquid refrigerant into the header 14 through the pipe 1'7, despite the fact that some disturbance may be caused on the other side of the partition 17 due to the liberation of flash gas from the fresh refrigerant delivered into the well through the pipe 22. The pipe 21 communicates with the main feed line 11, and the flow of refrig-. erant through this pipe is regulated by an auto.- matic pressure controlled reducing valve 23. The uppermost gas chamber or portion of the accumulator 16 communicates with the main suction line 6 through a pipe 24, and the flow of gas through this pipe may be interrupted byan automatic electrically actuated shut-01f valve 25. A pressure actuated switch 26 is operable by the relatively low gas pressure in the accumulator 16 through a connection 2'7, and this switch will sub,- sequently be referred to as a low pressure switch. The low pressure switch is adapted to control the operation of one or more fans for circulating air through one or moreof the enclosures 13. If two of the units are disposed closely adjacent to each other, it may be desirable to provide only one switch 26 for controlling the air circulating fans of both of the units, and in that case it may also be desirable to utilize a, single thermostatic control for both units.

Referring to the typical wiring diagram of Fig. 2, this diagram is applicable to a system wherein the air circulating fans of two adjacent units are controlled by a common low pressure switch 26, and. wherein other control is effected by means of a thermostat which is common to both units. The wiring diagram is applicable to a two-phase system and comprises generally a main line 30 for supplying current for operating the motor 31 which drives the compressor 5, and for also supplying current to actuate the air circulating fans and the automatic shut-01f valves 25. Thermostats 32 disposed within the enclosures 13 cooperate with double pole relay switches 33 to control the operation of one or more of the shut-off valves 25 which may be solenoid actuated, as shown. The compressor driving motor is providedwith an automatic starter 34 which may likewise be operable by one of the low pressure switches 26', and the fans which circulate air through the several enclosures 13 are provided with automatic starters when excessive pressure is established at the dis charge side of the compressor. The low pressure switches 26, two of which are shown associated with the starters 35, serve to cut out a number of fan. motors each of which is independently protected by overload equipment, and the diagram of Fig. 2 discloses one starter 35 for each group of six single phase fan motors. Each low pressure switch 26 will function to stop the six corresponding fan motors, when the respective thermostat 32 has acted upon an adjacent magnetic or solenoid valve through one of the two-circuit relay switches 33, and after the temperature and pressure in the coils 12 of the cooling unit have risen sufficiently to actuate the switch 26. When the thermostat 32 returns to running position, the corresponding valve 25 will again open, whereupon thepressure will drop due to withdrawal of gas by the compressor, and the switch 26 will snap back into normal position to again start the air circulating fans. The circulating fans are preferably provided with independent controls 38 so as to permit any of the individual fans to be cut out of the system. The power line may be provided with suitable cut-out switches 36, 37 the latter of which control the operation .of the air circulating fans through the starters 35 and controls 38.

The operation of the system will now be described, and it may be assumed that asingle low pressure switch 26 is being utilized to control the circulating fans of both of the units shown in Fig. 1. It may also be assumed that a single thermostat 32 is being utilized to control both units, and the description may thereby be restrictedto the half of the diagram at the right hand side of sheet two. Assuming the cut-out switches 36, 37 to be closed, and also the switch in the auxiliary line disposed centrally of Fig. 2, the compressor 5 then operates'to receive gaseous refrigerant from the suction line 6 and to deliver the same in compressed form through the discharge pipe 7 to the condenser 9. In the condenser 9 the gaseous refrigerant is transformed into liquid refrigerant, and the liquid refrigerant is delivered through the feed line 11 to the several pressure controlled reducing valves 23.

These valves 23 serve to control the pressure at 1;

which the liquid refrigerant is delivered to the several evaporators, and the valves may be set to establish any predetermined inlet pressure for the several evaporators. The actual delivery of liquid refrigerant from the pipes 21 to the evap- 11 orators 12 through the pipes 22, 17, is automatically controlled by the float valves 19 disposed within the accumulator 16. These float valves 19 regulate the quantity of liquid refrigerant at the pressure established by the valves 23, deliv- 1:

cumulator 16 and is eventually returned to the 1 compressor suction line 6 through the pipes 24 and past the electrically controlled shut-01f valves 25 which are normally open.

If the temperature in either of the enclosures 13 should drop below or increase above a predetermined desirable limit, the thermostat 32 will automatically function through the relay 33 to close the shut-off valves 25 and thereby prevent escape of refrigerant from the accumulator 16 to the suction line 6. Such operation of the shutoff valves 25 will take place when over feeding of liquid refrigerant to the units occurs, and will thus positively prevent delivery of slugs of liquid refrigerant from the units to the suction line. When such over feeding of liquid refrigerant oc- 1 curs, the pressure controlled reducing valves should be adjusted to prevent the undesirable condition of operation. The float controlled valves 19 will also prevent possibility o over feeding and will shut off communication between 1 the pipes 21, 22 when the level of liquid refrigerant within the accumulator 16 reaches a predetermined maximum height.

The automatic low pressure switches 26 serve to automatically out out the air circulating fans 1 and to start the same, so as to prevent excessive accumulation of frost on the heat transferring surfaces of the evaporators 12. When the frost has been removed from these surfaces, the fans will be automatically stopped, and will not be placed in operation again until further objectionable frost appears upon the surfaces. In this manner maximum economy in operation of the system, is obviously efiected.

From the foregoing description it will be apparent that the several automatic controls cooperate to eliminate objectionable operation of any units associated with a common refrigerant supply'source such as the compressor 5 and the condenser 9. The pressure reducing valves23 control the pressure at which the liquid refrigerant is delivered to each evaporator 12, and also prevent over feeding during periods of inactivity of the units. The float controlled valves 19 serve to regulate the quantity of liquid refrigerant delivered to each of the evaporators 12, and the electrically controlled shut-off valves 25 serve to prevent undesirable delivery of liquid refrigerant to the common suction line. The low pressure switches 26 cooperate with these various flow supply and control valves, to insure most desirable operation of the circulating fans, thus producing a system in which the control is entirely automatic. The improved system has proven highly successful in commercial operation, and permits effective utilization of a common refrigerant supply source for any number of units located either closely adjacent to eachother or at remotely spaced localities.

It should be understood that it is not desired to limit the invention to the exact details of construction and to the precise mode of operation herein shown and described, for various modifications within the scope of the claims may 00- our to persons skilled in the art. It is to be speciflcally understood that the control of the several evaporator units may be entirely independent, and that the invention is also readily applicable where two or more of these units are simultaneously controlled independently of other units forming a part of the complete system.

It is claimed-and desired to secure by Letters Patent:

1. In a refrigerating system, a compressor, an evaporator, an accumulator, means for controlling the pressure of the refrigerant delivered from said compressor to said evaporator, means operable by the level of liquid in said accumulator for controlling the quantity of refrigerant delivered to said evaporator, thermostatically controlled means for shutting-01f the flow of refrigerant from said evaporator to said compressor, and means operable by pressure within said system for controlling the circulation of air in proximity to said evaporator.

2. In a refrigerating system, a compressor, an evaporator, an accumulator, a pressure controlled reducing valve for controlling the pressure of the refrigerant delivered from said compressor to said evaporator, a float controlled valve operable by the level of liquid in said accumulator for controlling the quantity of refrigerant delivered to said evaporator, a thermostatically controlled valve for shutting-off the flow of refrigerant from said evaporator to said compressor, and means operable by the pressure within said accumulator ating with each of said evaporators, means for controlling the pressure of the refrigerant delivered from said compressor to each of said evaporators, means operable by the level of the liquid in each of said accumulators for controlling the quantity of refrigerant delivered to the corresponding evaporator, thermostatically controlled means for shutting-off the flow of refrigerant from said evaporators to said compressor, and me ms operable by pressure within the system for controlling the circulation of air in proximity to said evaporators.

4. In a refrigerating system, a compressor, a plurality of evaporators, an accumulator cooperating with each of said evaporators, means for independently controlling the pressure of the refrigerant delivered from said compressor to each of said evaporators, means operable by the level of liquid in each of said accumulators for independently controlling the quantity of refrigerant delivered to the corresponding evaporator, thermostatically controlled means for shutting-off the flow of refrigerant from each of said evaporators to said compressor, and means operable by pressure within said system for controlling the circulation of air in proximity to said evaporators.

5. In a refrigerating system, a compressor, an evaporator, an accumulator, a pressure controlled reducing valve for controlling the pressure of the refrigerant delivered from said compressor to said evaporator, a float controlled valve operable by the level of liquid in said accumulator for controlling the quantity of refrigerant delivered to said evaporator, a thermostatically controlled valve for shutting-off the flow of refrigerant from said evaporator to said compressor, and means operable by the pressure within said accumulator for controlling the operation of said compressor.

6. In a refrigerating system, a compressor, a plurality of evaporators, an accumulator cooperating with each of said evaporators, a reducing valve for independently controlling the pressure of the refrigerant delivered from said compressor to each of said evaporators, a float controlled valve operable by the level of liquid in each of said accumulators for independently controlling the quantity of refrigerant delivered to the corresponding evaporators, thermostatically controlled means for shutting-01f the flow of refrigerant from each of said evaporators to said compressor, and means operable by pressure within the system for controlling the operation of said compressor.

'7. In a refrigerating system, a compressor, a plurality of evaporators, an accumulator cooperating with each of said evaporators, means for controlling the pressure of the refrigerant delivered from said compressor to a selected number of said evaporators independently of other evaporators in the system, a float controlled valve operable by the level of the liquid in one of said accumulators for controlling the quantity of refrigerant delivered to a. selected number of evaporators independently of the delivery to other evaporators, and thermostatically controlled means for shutting-oi the flow of refrigerant from said evaporatdrs to. said compressor.

8. In a refrigerating system, a compressor, a plurality of evaporators, an accumulator cooperating with each of said evaporators, means for controlling the pressure of the refrigerant delivered from said compressor to a selected number of said evaporators independently of other evaporators in the system, means operable by the level of the liquid in one of said accumulators for controlling the quantity of refrigerant delivered to a selected number of evaporators independently of the delivery to other evaporators, and means operable by pressure within the system for controlling the circulation of air in proximity to selected evaporators.

9. In a refrigerating system, a compressor, an

evaporator, an accumulator having a well divided flow of refrigerant from said evaporator to said compressor, and means operable by pressure within said system for controlling the circulation of air in proximity to said evaporator. I

10. In a refrigerating system, a compressor, an evaporator, an accumulator having a well divided into segregated compartments communicating upwardly with the accumulator chamber, means operable by' the level of liquid in the accumulator chamber for controlling the delivery of refrigerant from said compressor to one of said compartments, and means for conducting refrigerant from the other of said compartments to said evaporator.

ERNST S. H. BS. 

